Author Topic: 40 / 60 weight distribution  (Read 2006 times)

in4

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40 / 60 weight distribution
« on: August 22, 2023, 05:38:48 pm »
Iíve not come across this idea/convention regarding weight distribution before. Iíve tended to keep my front forks light believing it was better in terms of steering. This idea suggests putting more weight on the front than Iíd usually do. Better balance I guess. Anyone stick closely to this suggestion?

Matt2matt2002

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Re: 40 / 60 weight distribution
« Reply #1 on: August 22, 2023, 05:51:09 pm »
Funny you should raise this point since I had just been thinking about tire pressures, front and rear.

I have read that when braking a lot of the total weight shifts forwards and so both tire pressures should be equal.

I'd be interested to hear other folks experiences / views. At the moment I run the rear tire pressure slightly greater than the front.

But there's always something to learn...
Never drink and drive. You may hit a bump  and spill your drink

mickeg

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Re: 40 / 60 weight distribution
« Reply #2 on: August 22, 2023, 06:51:33 pm »
Where did the 40/60 concept you mention come from?

I usually run my front tire pressure at about 67 to 75 percent of what my rear tire pressure is.

I think that only the narrower tires should be a concern about too low a front tire pressure during braking, as those are the tires that occasionally get pinch flats.

In USA, some are experimenting with using a front rack with panniers, maybe a front handlebar harness, but in rear either a saddle bag or rear rack with a bag on top.  Thus, it could easily have more luggage weight up front than in back.


in4

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Re: 40 / 60 weight distribution
« Reply #3 on: August 22, 2023, 07:05:10 pm »

Danneaux

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Re: 40 / 60 weight distribution
« Reply #4 on: August 22, 2023, 07:24:59 pm »
These links and my long-ago photo (~2012) where I weighed my actual weight distribution on my Nomad (used a couple of scales) may prove helpful to the discussion...

http://thorncyclesforum.co.uk/index.php?topic=6055.0
...and...
http://thorncyclesforum.co.uk/index.php?topic=4515.0

Best, Dan.
« Last Edit: August 22, 2023, 07:26:43 pm by Danneaux »

mickeg

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Re: 40 / 60 weight distribution
« Reply #5 on: August 23, 2023, 02:01:49 am »
I tried to weight front and rear on a bike, one scale and one piece of wood about the same height as the scale.  That was over a decade ago.  I think I only weighed the weight on one wheel. Then weighed my self on a scale with a bike on a scale for total.  No panniers, water bottles, etc.

If I recall correctly, I was trying to figure that out for purposes of the 15 percent Tire Drop theory in a Jan Heine article.
https://www.adventurecycling.org/default/assets/resources/200903_PSIRX_Heine.pdf

mickeg

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Re: 40 / 60 weight distribution
« Reply #6 on: August 23, 2023, 02:18:09 am »
My general thoughts on distribution of touring loads, not distribution of weight on a bike that is not carrying touring gear:

Some bikes handle front loads better than others.  I have close to zero expertise on frame geometry, but I have heard that long trail bikes (trail at the fork) are better for a more rear centered load while low trail bikes favors a front load better.  I am sure that is largely due to wheel flop, I have no clue if other factors come into play.

And some bikes have fairly flexible frames, I would expect that a front load is better on those.

If a bike has short chain stays, I would want to keep the rear loaded lighter than if it had long chainstays.  If your load on the back is too far above and behind the rear axle, it can have a tail wagging the dog sort of feel.

I tried putting a LOT of weight on the back of my Nomad Mk II one time when I had the suspension fork fitted.  It was not happy with that.  Otherwise, the Nomad Mk II can pretty much take any kind of load I put on it.  I can move weight fore and aft, and side to side on that bike and it does not protest at all.

My Sherpa also does not have a problem with weight distribution that varies from day to day.

I usually pack up my front panniers with the denser stuff in front.  The tent is always in the front right pannier. 

PH

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Re: 40 / 60 weight distribution
« Reply #7 on: August 23, 2023, 11:01:43 am »
I think these rules are a good starting point, but once you've done a few rides and experimented a bit, you find what works for you.  As said above there's a big difference between bikes, the French low trail bikes have always favoured a front load. It also depends on that load, and the proportion of it you can adjust.  For example, a 70kg rider with a 30kg load has the ability to manipulate more than a 90kg rider with a 10kg load. As a 100kg rider with not more than a 15kg load, I find it makes little difference how I distribute the luggage. My Mercury is very sensitive to any load over a couple of kg, but I quickly get used to it.  It makes little difference to the Nomad, other than being felt on hills and generally being a bit slower, it rides the same loaded or unloaded.  I have used front panniers, which do steady the steering at most riding speeds, but there's a point where that's reversed.  It's a long time since I toured with four panniers, I might at some point use lightweight front fork bags, but I doubt I'll ever go the front rack route again.  If I ever find myself wanting to transport huge loads, I'll use a trailer.

Andre Jute

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Re: 40 / 60 weight distribution
« Reply #8 on: August 23, 2023, 03:04:50 pm »
These links and my long-ago photo (~2012) where I weighed my actual weight distribution on my Nomad (used a couple of scales) may prove helpful to the discussion...

http://thorncyclesforum.co.uk/index.php?topic=6055.0
...and...
http://thorncyclesforum.co.uk/index.php?topic=4515.0

To separate the theoretical structure of bike roadholding and handling from this enjoyable thread of mainly seat of the pants practical wisdom, I've started a companion thread. "The pivot points and lever arm lengths of bicycle roadholding and handling", at
http://thorncyclesforum.co.uk/index.php?topic=14952.0

mickeg

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Re: 40 / 60 weight distribution
« Reply #9 on: August 23, 2023, 03:36:44 pm »
I live near a large university campus.  Huge variety of bikes there, range from half century old cotter pin cranks and 27 inch tires to modern bikes and a growing number of e-bikes.

I have been surprised recently when riding through campus how many bikes I saw that had a front low rider rack.  Some of those bikes lacked the rear rack, thus they were intended to only use front panniers and possibly a rackless rear bag like a saddle bag.  And some some students that were using one pannier on a front low rider rack, which surprised me.

I often use one rear pannier around town, my gym bag is a pannier.  And sometimes use one grocery shopping type of pannier in back.  But one front pannier just does not look right.

When I come home from a tour, the front low rider rack is removed.


Andre Jute

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Re: 40 / 60 weight distribution
« Reply #10 on: August 23, 2023, 04:18:04 pm »
I'd say yours is the classical way of loading a bike, George. Maybe those students use their bikes only for commuting to college, in which case it might not matter so much that the bike is unbalanced. If they were to go on tour with an unbalanced bike though, they'd soon enough work out for themselves, or be told by someone more experienced on the road, that balance matters -- and how best to achieve it.

A single lowrider might just be this week's fashion...